Control instrument housing

ABSTRACT

Control instrument unlatchable and pullable out of its housing by means of latch-operating handle retractable into front of instrument, and having recess-mounted, removable name plate in front end.

United States Patent Inventor Hugh .1. Tyler Santa Ana, Calif. Appl. No. 829,674 Filed June 2, 1969 Patented June 22, 1971 Assignee Syhron Corporation Rochester, N.Y.

CONTROL INSTRUMENT HOUSING 9 Claims, 8 Drawing Figs.

US. Cl 40/ 10, 334/85, 292/86 Int. Cl G091 3/18 Field of Search 40/10, 16,

[56] References Cited UNITED STATES PATENTS 1,195,759 8/1916 Wright 40/325 2,812,600 11/1957 Hopp. 40/16.2 3,024,555 3/1962 Abeles.. 40/331 3,044,069 7/1962 Klumb 73/431 X Primary Examiner-James A. Leppink Assistant Examiner-Robert L. Wolfe AttorneysPeter J. Young, Jr. and Joseph C. MacKenzie ABSTRACT: Control instrument unlatchable and pullable out of its housing by means of latch-operating handle retractable into front of instrument, and having recess-mounted, removable name plate in front end.

PATENTEI] JUH22 IHYI SHEET 1 BF 2 QINVENTOR. HUGH J. TYLER PATENTED JUH22 197i SHEET 2 [IF 2 INVENTOR.

--HIUGH J. TYLER N GE CONTROL INSTRUMENT HOUSING The Field of the Present Invention is pneumatic, electrical and analogous instruments having various facilities for measuring, controlling, recording, indicating, and/or the like, useful in control of industrial processes, and the like.

The Background of the Invention is that heretofore such instruments have been mounted in housings which envelope or embrace the major part of the instrument except the fore-portions or faceplates thereof. These faceplates ordinarily have various entities thereon which are arranged for view and/or manipulation, and which relate to, are, or form part of said facilities. See, for example, US. Pats. No. 2,803,451, 3,025,868 and 3,433,239, each assigned to the assignee of the present invention, and representative of the prior art. (The particulars of such prior art instruments are neither essential to support the claims appended hereto, nor essential for adequate disclosure of the invention (35 USC I I2).

In a given case, an instrument would be, in essence, a chassis or like structure mounting a collection of said entities and removable from the housing, as by releasing a latch, pulling on a handle, and/or the like, so as to free the chassis from the housing and extract it therefrom. Applicant does not believe particularizing prior art housings, latches, etc. would serve any useful purpose here, since those skilled in the art are quite aware of such. (In this connection, it is to be remarked that housings, latches, and the like, are among the most ancient of entities to which human ingenuity has been accustomed to apply itself). Suffice it to say that, in general, prior art housing and latching arrangement tend toward the complex. The present invention is characterized by a relatively simple housing and latching arrangement having relatively complex latching and unlatching function, obtained by relatively simple mechanism.

In Summary, according to the invention, the face plate of an instrument has a slot therethrough, and, supported within the confines of the instrument, there is a member biased to move out of the instrument when appropriately manipulated, which will then serve both to release a latch mechanism holding the instrument in its housing and to pull the instrument out of its housing. Further, the faceplate has a shallow recess therein, in which an elastic nameplate is removably sprung in place.

In the drawings, FIG. 1 is a perspective, exploded view of an instrument, housing and latch mechanism according to the invention. FIGS. 2 through 5 are substantially fragmentary sections taken on the plane A-A of FIG. I, and to approximately lzl scale. FIGS. 6 and 7 are respectively a partial front elevation, and a partial section therethrough on the plane B-B vertical to the plane of FIG. 6, and FIG. 8 shows a mechanical detail, in perspective, on the scale of FIGS. 2 through 5.

In FIG. 1 is shown the faceplate I and chassis 2 of a typical instrument, partly withdrawn from its housing 3. Housing 3 is shown as the common, rectangularly parallelipipedal box, the open end of which terminates in escutcheon 4, with which faceplate 1 and a suitable more or less decorative frame (not shown) cooperate to close the open end of housing 3 when chassis 2 is thrust all the way into housing 3.

Chassis 3 is normally more or less packed with sundry electrical, mechanical, pneumatic, and/or like elements, which commonly make up a control instrument. Such elements are not shown here, since they are not relevant to making and using the invention. However, as shown in the patents cited above, such elements may include a variety of entities such as electrical and/or pneumatic switches, amplifiers, meters, motors, recorders, alarms, signals, and so on, along with such wiring, piping and hardware as is needed to interconnect the enumerated elements for use in control, measuring, and so on. Also not shown are external entities which would customarily relate to the instrument. For instance, wiring and/or piping would connect the instrument to certain of such entities. The housing 3, further, would be mounted by, in or on some such entity, such as a panel, cabinet, rack, and the like. Those skilled in the art are familiar enough with such elements and entities that it is unnecessary to describe same further herein.

The chassis 2 is composed essentially of front, side, and bottom plates 5, 6 and 7 composing an integral whole conveniently though not necessarily formed from sheet metal by suitably bending and punching operations.

Front plate 5 and faceplate l are essentially one, functionally speaking, though shown as distinct entities. Insofar as the present invention is concerned, sideplate 6 is merely a convenient element on which to support the later-to-bedescribed latch mechanism. Likewise, plate 5 is merely a convenient element on which to support the faceplate 1. Faceplate 1, in turn, is shown as relatively complex shaped entity. It is typically a metal casting since it is rather more economical and practical to produce it as a complex shape of good appearance, by casting than from by sheet metal workmg.

Front plate 5 has a rectangular cutout 8 therein which is normally substantially filled with a scale plate 9, which latter is shown exploded out of position, however. Scale plate 9 has a suitable'scale of indicia thereon, representing the fact that in this instance one of the entities on the bottom plate 7 of chassis 2 would be an indicating mechanism (not shown), e.g., a pressure gauge, milliammeter, or the like,'which would have a pointer (not shown), the indicating end of which would move vertically along the side of the scale plate 9 to indicate pressure, electric current, or the like, in terms of the aforesaid scale ofindicia.

Faceplate 1 has a vertical through-opening 10 therein corresponding in area to said scale plate. When the faceplate l is assembled to front plate 1, scale 9 and the aforesaid pointer would be approximately located in the opening 10 and visible therethrough through suitable glazing indicated at 11.

As shown, chassis 2 is partly out of housing 3. Fully in, the faceplate I may substantially entirely close the open end of housing 3, see FIGS. 2, 3 and 4, for example. A handle 12 provides, however, for pulling the chassis out to the position shown (or to one not so far out of the housing 3, or further out of the housing 3).

Handle 12, as will later be seen more precisely, is supported in and behind the faceplate I, and projects through the front and faceplates via vertical slots 13 and 14.

Handle 12 has a grip 15 which may be grasped in the fashion of a handgun butt to pull the handle out (though normally not so far as shown in FIG. 1, of course). Slot 14 is of sufficient depth and vertical dimension to approximately entirely receive grip 15 except for serrations 16, the vertical dimension of both slots 13 and 14 allowing a certain amount of vertical play to such of the handle 12 as is confined therein, even when the handle 12 is pushed all the way in (to the left, from the view point of FIG. 1).

The vertical play of the handle 12 provides for operating a latch mechanism according to the invention. Such latch mechanism includes a catch 17 mounted on a vertically deflectible cantilever 18, which may be a blade spring fixed by a bracket 19 to the sideplate 6 for such deflection. As shown, holes 20 in sideplate 6 provide for securing bracket 19 to the sideplate by means of bolts, or the like.

Likewise, a guide plate 21, for mounting on sideplate 6, as by means of bolts, or the like, passing through suitable holes 22 in the guide plate 21, and suitable holes 23 (only one of which is visible) in the sideplate 6, provides for both the aforementioned vertical play and push and pulling of handle 12. Thus, the handle 12 normally passes through a slot 24 in plate 21, of sufficient vertical dimension to allow vertical play to the handle 12.

From the foregoing, it will be evident that handle 12 is variously guided and supported for motion along the direction of its long dimension and for deflection vertically about a horizontal axis normal to said direction. This axis, as will be seen later, is located at the bottom edge of slot 24.

Handle 12 has a cam 25, the leading edge of which is for butting up against a later-to-be-described part of the latch mechanism. The handle also has a front notch 26 providing a leading edge for also butting up against the back of faceplate I. These buttings up are provided for by a spring 27, even if the handle 12 is not being pulled on manually. Thus, one end of spring 27 fastens to an ear 28 on guide plate 2ll and its other end hooks in a rear-notch 29 in handle 12, and urges the handle outwardly in all positions thereof.

Guide plate 24 is so located on sideplate 6 that at the farthest extraction of handle 12 through the front of the instrument (rightward, as seen in the drawing, but not, of course, so far extracted as shown in FIG. 1), the tension of spring 27 has leverage on handle 12 about the aforesaid axis that is enough to deflect handle 12 upwardly (actually, counterclockwise, from the point of view of FIGS. 1 through so that the topside 30 of the handle 12 is forced against the top edge of slot 14.

It will be observed that FIG. 1 indicates that if the handle is pulled on in the direction of extracting it, the handle 12 could come out so far as to make the leading edge of cam 25 butt against the back of front plate 1. Then, if one pulled hard enough on the handle in this way, the chassis 2 could be extracted from housing 3, all other things being equal.

However, to extract the housing it is necessary to unlatch the chassis by freeing catch 17. Catch 17 is essentially a teat 33, or the like, receivable within a hole 34 in the topside 35 of housing 3. (Of course, the teat could be on the housing, and the hole could be in the catch, and so forth.) When the chassis is all the way in the housing, hole and teat are so located as to interengage and oppose extracting the chassis from the housing; see FIGS. 2 and 3. At this time, the handle is either fully retracted, with the leading edge of notch 26 butting up against the back of front plate 5, adjacent the upper end of slot 13, or it is fully extracted, though not yet causing the catch 17 to release.

The cantilever 18 is so positioned so that its natural elasticity forces a pad 36, which forms part of catch 17 and has teat 33 projecting therefrom, against the inside surface of the topside 35 of housing 3. Hence, to pull the chassis out, it is necessary to bend the cantilever 18 down (actually, clockwise, from the point of view of the drawings), and a crank 37 provides for doing this.

The crank 37 has a pivot 38, in the form of a lug struck out of the material of the crank, which defines an axis of deflection for the crank parallel to the previously mentioned axis, but fixed in position. For the purposes of FIG. 1, the crank axis is at the back of plate 5 at the upper edge of slot 13.

When the teat 33 and hole 34 interengage, the arm 40, which has a hole or fork 48 (see FIG. 8), receiving the shank of a stud 42 having a head 43 too large to pass through the hole 48, is pulled up by lever 18. The lever 18 then holds the crank 37 with its arm 40 in a position of approximately 30 above the horizontal, and with arm 39 deflected about as much clockwise from the vertical.

At this time, arm 39 extends downwardly far enough that it would interfere with handle 12, except for a side notch 44, which, in effect, allows the handle to pass through arm 39. However, the notch 44 terminates vertically sufficiently close to the top edge 30 of handle 12 that the leading edge of cam 25 catches on the upper edge of notch 44, if the handle 12 be extracted.

It will be seen, therefore, that extracting handle 12 far enough will deflect arm 39 counterclockwise. Arm 40 will follow, and pull cantilever 18 down since the head 43 of stud 42 cannot pass through arm 40. Consequently, teat 33 will disengage from hole 34. Being unlatched now, chassis 2 can be extracted from housing 3 by pulling on handle 12, since the leading edge of cam 25 is now butted up (via arm 39) against front plate 5.

It will be noted that the tension of spring 27, because of the orientation of the spring, applies an extracting force to the handle 12. However, when the handle 12 is pushed inwardly of the instrument far enough, the leading edge of notch 26 passes behind the plate 5. Since the spring 27 is also trying to deflect handle 12 counterclockwise, the notch 26 tends to engage the upper, back edge of slot 13 of plate 5, so that if the spring now tries to push the handle out, the leading edge of notch 26 will butt up against the back of plate 5. Accordingly, the tension of the spring is chosen to be large enough to maintain notch and slot edge interengaged, when the grip I5 is released from manual grasp. This leaves handle 12 all the way retracted except for the serrations 16 on grip 15. In order to extract the handle 12, one therefore gets a thumb purchase on the handle by means of the serrations, pushes downwardly to disengage slot edge and notch, and allows the tension of spring to push the handle 12 out. Almost simultaneously, one's thumb and a finger or two can be shifted into a sort of piston grip on gri'p 15 and the emerging portion of handle 12, with which to pull on the handle to free catch 17 and pull the chassis out of the housing immediately thereafter.

It will be noted that in pulling the chassis 2 there can be a tendency to lift upward on the handle. In some cases, this upward lift can cause binding. For instance, a sharp upper edge, such as plate 5 can have, can'catch on the casing 3 (except if casing 43 is flared at its opening, as escutcheon 4 provides). It is merely necessary in these cases to modify the piston grip by placing the thumb over the top edge of the faceplate 1 and pressing the thumb down, which reverses any upward tendency of the extracting force, thereby preventing binding.

FIGS. 2 through 5 illustrate various stages of the abovedescribed events.

Having gotten the chassis partly out of the housing, if the handle is released, the configuration of FIG. 5 results. Here spring 27 is urging handle 12 clockwise, so that the handle assumes a position determined by the reactions to the spring force at the lower edge of slot 24 and the upper edge of slot 14. Cantilever 18 is substantially free except for clockwise moment exerted on it by spring 27 via handle 12 and crank 37. However, as the stiffness of the cantilever is preferably relatively large as compared to that of spring 27, cantilever 18 is substantially undeflected.

It will be observed that pivot 38 provides its pivot function 7 simply by extending into a hole 45 in front plate 5. The hole 48 in arm 40 is preferably formed (slightly oblong as shown in FIG. 8) so that the stud 42 is retained thereby, relatively loosely in order to permit the crank to assume the various positions shown in FIGS. 2 through 5, without binding on stud 42 or arm 38. As will be seen from the relative positions of cantilever 18, front plate 5 and handle 12, the crank is substantially constrained to deflect about a pivot axis (normal to the plane of FIGS. 2 through 5) in hole 45. Thus, the leading edge of cam 25, urged by spring 27, urges the pivot 38 against the upper edge of hole 45. At other times, when the cam 25 is not in contact with arm 39, the center of gravity tends to maintain contact of pivot 38 with the upper edge of hole 45. In any event, confined as crank 37 is, pivot 38 cannot move far from the upper edge of hole 45, and cannot at all get out of the hole, unless the latch mechanism as a whole is substantially disassembled.

FIG. 4 shows the lever with the catch 17 released, just enough retracting force having been applied to handle 12 to bend the cantilever 18 down so that the catch 17 is clear of hole 34 in topside 35 of housing 3. The construction of the instrument will normally be such that moving the chassis will take more force than it does to bend cantilever 18. Under various circumstances it would be possible for teat 33 to bind against the edge of hole 34 due to slight outward motion of the chassis. However, a counterforce, exerted by the thumb of the hand on the handle 12 will readily free the teat.

In FIG. 3, the retraction has gone only so far as to have moved handle 12 just to the point of cam 25 engaging crank 37, and teat 33 is in hole 34, with pad 36 engaging the housing surface around the periphery of the hole. It is, of course, not desirable to leave the grip 15 projecting from the faceplate 1, as shown in FIG. 3, so normally, if the handle 12 is not in use, it is pushed in the position shown in FIG. 2, where only the serrations 16 project from the faceplate l.

Pushing the handle 12 in is opposed by the spring 27. So when the handle is pushed in so far that the notch 26 clears the rear edge of the top of slot 14, the grip end of the handle is pushed up and released so that the leading edge of notch 26 butts against the rear edge of the top of slot 14. Between spring 27 and the edge to edge friction, the handle 12 will remain deflected up, i.e., as shown in FIG. 2. To release the handle 12, one simply places a thumb or finger on the serrations 16, pushes down and then withdraws thumb or finger slightly so that the top surface 30 of handle 12 can pass into slot 14. One may then release the handle 12 entirely, whereupon spring 28 will push handle 12 out to the position shown in FIG. 3.

Grip is shaped to automatically assure locking the handle 12 in place. Thus, as one pushes handle 12 in from the position shown in FIG. 2, the slanted facet 46 of grip 1S strikes the front edge of the lower end of slot 14. The leading edge of slot 26 will be so located that at this point it is through the slot 14 and behind faceplate 1. Therefore, further pushing on grip 15 will make it climb, so to speak, the front edge of the lower end of slot 14. This will bring the leading edge of notch 26 above the level of the edge of the upper end of slot 14, and between this pushing and the tension in spring 27, the said leading edge assumes this position substantially immediately upon the topside 30 clearing the back edge of the upper end of slot 14. In the same way, facet 46 assists extracting the handle, i.e., in going from F 1G. 2 position to FIG. 3 position.

The vertical dimension of slot 13 provides the vertical clearance necessary for the slight vertical motions which handle 12 has to go. Slot 13 has little else to do, although it will be observed that if spring 27 broke or were omitted, the lower edge of slot 13 would prevent any basic derangement of the latching mechanism, though naturally the handle would likely extrude to the extent shown in FIG. 3 (or less, but not more, unless pulled). Hence, the latching mechanism would remain essentially functional despite absence of the force of spring 27.

Slot 14 is a little lesser in vertical dimension than the vertical dimension between topside 30 and the horizontal containing the point on facet 46 first contacting the lower edge of slot 14. This is so in order to provide the previously described effect of facet 46, and to assure that the serrations 16 do not go too far into the slot 14 to be inaccessible to thumb or finger. On the other hand, this latter function can be provided by a cam 47 on handle 12, which also limits how far the handle 12 can be pushed into the casing. Therefore, vertical dimension of the slot 14 is not critical, since notch 26 can be caused to engage the upper edge of slot 12 (as shown in FIG. 2) solely by a little care in manipulation and taking advantage of the tendency of the notch to thus engage under the urging of spring 27.

The assembled position of plates 1 and 5, with respect to each other, is as shown in F168. 2 through 5, though no particular means for doing so are illustrated. ln practice, pillars, webs, or the like (not shown), which rest against front plate 5,

project from the back of faceplate 1, and a few bolts, or the like, secure the plates together. Thus, as indicated in FIGS. 1 and 6, a bolt 49 may pass through a suitable hole in the faceplate and screw into a threaded hole 50 in front plate 5. In addition, holes 51 and 52 are provided in plate 1, and a hole 53 is provided in plate 5. Hole 51 provides for access or inspection of hole 45 with pivot 38 therein, and holes 52 and 53 provide for removing a nameplate 54 which normally covers holes 51 and 52.

Plate 54 is made of springy metal or plastic and is sprung into place in a shallow recess 55 of plate 1. The bottom of recess 55 is flat except at fillets 56 at the sides of the bottom of recess 55. As can be seen from FIGS. 1 and 7, the fillets slope down toward the bottom of the recess. A pair of lugs"57 project over the bottom of the recess 55 from the centers of the long sides thereof. The fillets and lugs are so located and dimensioned that the nameplate can be freely slid under the lugs from either end of the recess for only a short distance without flexing the plate, or at least by the time one end of the nameplate has begun to climb one of the fillets 56. Fully in the recess, name plate 54 has its middle bowed by lugs 57 toward the bottom of the recess, and its ends bowed away from said bottom, by fillets 56. That is to say, the name plate is sprung in place, and between the stress in it and the friction of its engagement with fillets and lugs, is tightly held in place.

To remove the nameplate, one takes a pencil, screwdriver, or the like, thrusts it against the back of the nameplate, via holes 52 and 53, which are in registry, and forces one end of the nameplate 55 out of the recess far enough to grasp it by the fingers or a suitable tool. The nameplate can then be slipped out. This permits the hole 45 and pivot 38 to be inspected, the name plate to be replaced, or bolt 49 to be gotten at, and so on.

it will be observed that handle 12, cantilever 18, and crank 37 constitute, functionally, two four-bar linkages. Two fourbar linkages imply five moving bars (one of which would be common to both linkages) and six pivot points. Handle 12, cantilever 18, and crank 37, however, provide the effect of these six pivots, without using pivot pins, or the like, such as require journals, fixed bearings, and so on. Finally, the motions involved are relatively complex, that is, handle 12 provides straight line motion, part of which is lost motion (FIG. 2 to P10. 3, and vice versa) as well as angular motion, and these motions, along with the angular motions of crank 37 and cantilever 18 involve three sliding pairs (at slot 24, arm 39 and stud 42). Nonetheless, the structure involved is simple and tolerant of manufacturing variations in dimension. 7

The structure illustrated approximates closely that of an actual example of an instrument according to the invention. Hence, the shape and nature of many of the parts represent specific particulars of the designers skill, to which particulars there are alternatives. For instance, the cantilever 18 could be rigid and pivoted by a fixed axle to sideplate 6, in which case a separate spring would be needed to maintain catch 17 engaged, in lieu of using the inherent stiffness of the cantilever 18 to do so. Other such modifications will be evident to those skilled in the art and would be regarded as within the scope of my invention as claimed.

Having fulfilled therequirements of 35 USC 112 as to disclosing my invention and the manner of using it, 1 claim:

1. In an instrument having an open-ended housing, and a faceplate closing the open end of said housing, said faceplate having an inside facing into the housing, and an outside facing outwardly of the housing for viewing externally of said housing; said instrument also having a nameplate having an in-surface facing said outside and an out-surface facing oppositely so as to be viewable like said outside; first means on said outside and contacting first portions of said in-surface; second means on said outside and contacting second portions of said out-surface, at least some of said first portions alternating with said second portions, and there being at least four portions; said name plate being made of springy material, each said first means exerting a first force against each said first portion of said in-surface of said nameplate and each said second means exerting a second force against each said second portion of said out-surface of said nameplate said first force and said second force being oppositely directed.

2. The invention of claim 1, wherein said plate has a passage therein opening at one end on said outside of said faceplate and opening at the other end of one side of said faceplate at a location wherein a tool can be inserted into said passage via the opening of said other end; the opening of said one end of said passage being under said nameplate.

3. The invention of claim 1, wherein said opening of said other end of said passage is on said inside of said faceplate.

4. The invention of claim 1, wherein said first means includes a lug on said faceplate and extending over said outface of said nameplate; and said second means includes a ledge on said faceplate and extending above the surface of said outface.

5. The invention of claim 4, wherein said surface of said outface is substantially coextensive with said nameplate, and said out-face has further surface surrounding the first said surface and projecting thereabove.

6. The invention of claim 1, wherein said means includes a pair of lugs extending toward each other and over said outface of said nameplate; and said second means includes a pair of ledges on said out-face and extending above the surface of said out-face.

7. The invention of claim 6, wherein said surface of said outface is substantially coextensive with said nameplate, and said out-face has further surface surrounding the first said surface and projecting thereabove.

8. The invention of claim 1, wherein said nameplate is a flatrectangular lamina, and said out-face has a substantially flat rectangular recess therein receiving said nameplate; said first means being a pair of lugs, one said lug projecting into said recess from one edge thereof, and the other said lug projecting into said recess from a second edge thereof; said second means beinga pair of ledges, one said ledge projecting from the bottom of said recess at a third edge thereof, and the other said ledge projecting from the bottom of said recess at the fourth edge thereof; said first and second edges being opposite edges of said recess, and said third and fourth edges being opposite edges of said recess.

9. The invention of claim 8, wherein one said ledge slopes down to the bottom of said recess toward the other said ledge.

2% UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION June 22, 1971 Patent No. 3,585,7 Dated Inventofls) Hugh J Tyler It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4 line 11 and 19, "piston" should read pistol- Claim 3, line 1, "1" should read -2--.

Signed and sealed this Lpth day of January 1972.

(SEAL) Attest:

EDWARD M.FLETCI-IER, JR. ROBERT GOTTSCHALK Attesting Officer Acting Commissioner of Patents 

1. In an instrument having an open-ended housing, and a faceplate closing the open end of said housing, said faceplate having an inside facing into the housing, and an outside facing outwardly of the housing for viewing externally of said housing; said instrument also having a nameplate having an in-surface facing said outside and an out-surface facing oppositely so as to be viewable like said outside; first means on said outside and contacting first portions of said in-surface; second means on said outside and contacting second portions of said out-surface, at least some of said first portions alternating with said second portions, and there being at least four portions; said name plate being made of springy material, each said first means exerting a first force against each said first portion of said in-surface of said nameplate and each said second means exerting a second force against each said second portion of said out-surface of said nameplate said first force and said second force being oppositely directed.
 2. The invention of claim 1, wherein said plate has a passage therein opening at one end on said outside of said faceplate and opening at the other end of one side of said faceplate at a location wherein a tool can be inserted into said passage via the opening of said other end; the opening of said one end of said passage being under said nameplate.
 3. The invention of claim 1, wherein said opening of said other end of said passage is on said inside of said faceplate.
 4. The invention of claim 1, wherein said first means includes a lug on said faceplate and extending over said outface of said nameplate; and said second means includes a ledge on said faceplate and extending above the surface of said out-face.
 5. The invention of claim 4, wherein said surface of said out-face is substantially coextensive with said nameplate, and said out-face has further surface surrounding the first said surface and projecting thereabove.
 6. The invention of claim 1, wherein said means includes a pair of lugs extending toward each other and over said out-face of said nameplate; and said second means includes a pair of ledges on said out-face and extending above the surface of said out-face.
 7. The invention of claim 6, wherein said surface of said out-face is substantially coextensive with said nameplate, and said out-face has further surface surrounding the first said surface and projecting thereabove.
 8. The invention of claim 1, wherein said nameplate is a flat-rectangular lamina, and said out-face has a substantially flat rectangular recess therein receiving said nameplate; said first means being a pair of lugs, one said lug projecting into said recess from one edge thereof, and the other said lug projecting into said recess from a second edge thereof; said second means being a pair of ledges, one said ledge projecting from the bottom of said recess at a third edge thereof, and the other said ledge projecting from the bottom of said recess at the fourth edge thereof; said first and second edges being opposite edges of said recess, and said third and fourth edges being opposite edges of said recess.
 9. The invention of claim 8, wherein one said ledge slopes down to the bottom of said recess toward the other said ledge. 